Circuit breaker



NOV. 20, 1951 GRISSlNGER ETAL 2,575,709

CIRCUIT BREAKER Filed Oct. 50, 1946 2 SHEETS-SHEET l WITNESSES: 6 66 'INVENTORSOI C 0 y 171310 78! an i Bernard 6: Tremb/gy,

ATTORNEY Patented Nov. 20, 1951 UNITED STATES PATENT OFFICE CIRCUIT BREAKER George G. Grissinger and Bernard G Tremblay, Wilkinsburg, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application October 30, 1946, Serial No. 706,736

15 Claims.

The invention relates to circuit breakers and, more particularly, to the type of circuit breaker used for controlling and protecting alternatingcurrent network distribution circuits.

In order to provide for tripping over a wide voltage range of circuit breakers used as network protectors, sensitive trip means having very light trip loads are utilized to trip the circuit breaker. When closing such circuit breakers by means of an alternating-current solenoid, trouble has been experienced due to the shock produced by the speed and sudden force with which the alternating-current solenoid operates its armature causing the light-load latch mechanism to move to unlatching position thereby effecting false opening of the breaker.

It i an object of this invention to provide an improved circuit breaker having a solenoid closing mechanism and a light-load trip means with means for preventing operation of the trip mechanism in response to shock produced by the closing mechanism.

Another object of the invention is to provide an improved circuit breaker having a light-load trip means and a solenoid closing means with means set in motion by the closing mechanism and operable when set in motion to prevent tripping operation of the trip means in response to shocks produced by the closing means.

Another object of the invention is to provide an improved circuit breaker having a light-load latch means and a solenoid operated closing means with means comprising means set in motion by the closing means and operable when set in motion to prevent tripping movement of the latch means for a predetermined time interval in response to sudden shocks produced by the closing means.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself,. however, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description of an embodiment thereof when read in conjunction with the accompanying drawings, in which:

Figure l is a front elevational view of a threepole circuit breaker embodying the principles of the invention.

Fig. 2 is a vertical sectional view taken substantially along line II-II of Fig. 1.

Fig. 3 is a single line diagram showing the mechanism in the tripped position, just before the main toggle has collapsed and the mechanism has been reset.

Referring to the drawings, the circuit breaker is of the three-pole type and comprises, generally, a base H, of molded insulating material, stationary contact means l3 and movable contact means l5 foreach pole, at common operating mechanism indicated generally at IT, a trip device IS and :a solenoid. closing means 2|.

The stationary contact |3 for each pole is secured to a conductor 23 which, in turn, is rigidly secured to the base ll by suitable means (not shown). The conductor 23 extends upwardly from the contact I3 and is secured at its upper end to the innerend of a bolt 25 which extends through the base I l to forma terminal connector for connecting the breaker in an electrical circuit. Thexmovable contact 15 for each pole is secured to a contact. member 21 which is loosely mountedon a channel-shaped switch arm 29 pivotally mounted on a. pivot pin 3|. The pivot pin Si is mounted in the two side members 33 of a U-shaped main frame35 which is mounted on and. projects. outwardly from the central portion of the base M. Cross members 37 and 39 integrally connecting the side members 33 adacent the basev H are. secured to the base by means of screws ll and 43. The contact member 21 is connected to a flexible shunt conductor 45 having its lower end secured to the base II and to the upper end of a. conductor 4'! by means of the screw 43.. The lower end of the conductor 41 is secured to theiinner end (not shown) by a bolt 49 secured to the base II and extending forwardly therefrom to. form a terminal connector.

The contact member 2:! is mounted on the channel-shaped switch arm 29 by means of a bolt 5| threadedly engaging an opening in the switch armand locked in place by means of a lock nut 53. The bolt 5| is provided with a head (not shown) which is engaged in a flanged recess (also not shown) in the contact member to loosely support the contact member. A spring 55 seated in a spring seat 51 and compressed between the springseat and the contact member provides contact pressure when the contacts are closed.

It will be understood that there is a stationary contact l3, movable contact |5,.contact,member 21 and channel-shaped switch arm 29 provided for each of the three poles of the breaker. Only the switch arm 29 for the center pole is mounted on the pivot pin 3| but all of the switch arms are connected together for unitary movement to simultaneouslymove .all of the switch arms to-open and closed positions. The means for connecting the switch members comprises a metal tie bar .59 which extends across all of the switch members adjacent the pivot .pin 3|. A sheath'ti of insulating material surrounds the tie bar 59 to insulate the several switch arms from each other. The tie bar is secured to each of the switch arms by means of metal clamps 53 which surround the insulating sheath 6| and are clamped to the switch arms. v

The operating mechanism comprises a main frame.

toggle consisting of toggle links 65 and 61 and a lever 69 pivotally mounted on a fixed pivot pin II supported in the side members 33 of the main The toggle link 65 comprises a pair of spaced parallel links joined by an integral cross member I3. The two legs of the toggle link 65 straddle the switch arm 29 for the center pole of the breaker and are pivotally connected to the sides of the switch arm by means of a pivot pin I5 the ends of which extend laterally beyond the frame members 33 to limit the opening movement of the switch arm 29 by engagement with the frame members. One end of the toggle link 81 is pivotally connected by means of a pin TI to the inner end of the lever 89 and the toggle links 65 and 61 are pivotally connected together by means of a knee pivot pin I9.

The outer end of the lever 69 is pivotally connected by means of a pin 8| to a tripping toggle comprising toggle links 83 and 85. The lower end of the toggle link 85 is pivoted on a fixed pivot comprising a pin 81 supported in the side member 33 of the main frame 35. The toggle links 83 and 85 are pivotally connected together by means of a, knee pivot pin 89.

Reference to Fig. l discloses that the toggle link 85 comprises spaced links connected at their upper ends by an integral cross member 9|, also that the toggle link 83 comprises spaced links joined at their upper ends by means of a pin 93 upon which is mounted a latch roller 95 which is engaged by a latch member 91 pivoted on a fixed pivot pin 99 supported in the main frame.

Referring to Fig. 2, it will be seen that the main toggle 656I is overcenter above a line drawn through thecenter of the pins I5, II, the

overcenter position of the toggle being limited by a projection I00 of the link 61 engaging the cross member .13 of the link 65. Thus the switch arm 29, which is biased in a clockwise direction by means of springs |0| tensioned between the switch arm and a rod I02 supported in the main frame, and the main contact springs 55, acts through the toggle 65-61 to bias the lever 69 also in a clockwise direction about its pivot 'II. Such clockwise movement of the lever 69 is normally prevented by the tripping toggle 8385. The tripping toggle is slightly underset to the left of a line drawn through the centers of pins 8|, 81. The force of the springs IN and 55 is applied through the main toggle 856'I and the lever 69 to the tripping toggle in a downward direction urging collapse of the tripping toggle 83--85. In order that the tripping toggle may collapse, it is necessary that the link 85 rotate counterclockwise about the fixed pivot 81 and the link 83 rotate clockwise about the pivot 8| on the,lever 69. Since the tripping toggle 83-85 is underset to the left of the line 8|8'I, the clockwise bias of the lever 69 by the springs |0I biases the link 85 of the tripping toggle in a counterclockwise direction about its pivot 81 and biases the link 83 of the tripping toggle in a clockwise direction about the pivot pin 8| on the lever 69. Collapse of the tripping toggle 83-,-85 is normally prevented by engagement of the latch 91 with the latch roller 95.

Upon operation of the trip device I9 in response to predetermined abnormal conditions in the circuit of any. one of the three poles, the latch member 91 is operated to unlatching position, whereupon the springs IM 'and 55 act through the switch arm 29 and the main toggle 65-61 and lever 69, to efiect immediate collapse of the tripping toggle 83-85 and opening of the contacts I3--I5. During the opening movement, the pin 15 connecting the toggle link 65 to the switch arm 29 is arrested by striking a portion I6 of the frame 35. This removes the biasing force of the spring I0| from the main toggle 6567 and from the lever 69. When this occurs the main toggle 85-61 collapses overcenter below the line through I5, I! and the weight of the parts aided by a spring I03 tensioned between the knee pin 89 of the tripping toggle and a rod I05 supported in the main frame, quickly resets and relatches the tripping toggle and rotates the lever 69 counterclockwise to the position shown in Fig. 2 in preparation for a contact closing operation.

The contacts are closed by means of the solenoid 2| which may be energized by suitable control means. (not shown) connected across two phases of the three-phase alternating-current circuit controlled by the breaker. The solenoid 2| is mounted by means of brackets I0'I secured to the fixed core member I08 (Fig. l) of the solenoid and to an angle bracket I09 which, in turn, is secured to a plate III. The plate I may be secured to the base II of the breaker or to the mounting structure (not shown) upon which the circuit breaker is rigidly supported. The solenoid 2| comprises the fixed core member I08, an energizing coil H3 and an operating armature II5. A pair of cars II'I one disposed on each side of the armature are secured thereto by any suitable means preferably by welding.

The ears I H are pivotally connected, by means of a pivot pin I2I, to the upper ends of a pair of closing links I23. The closing links I23 extend downwardly beside the frame members 33 of the mainframe and have their lower ends connected to the knee pin I9 of the main toggle, the knee pin I9 extending laterally through clearance openings I25 (only one being shown) in the side members 33 of the main frame.

After the circuit breaker has been tripped open and the tripping toggle reset and relatched in the previously described manner, the circuit breaker may be closed by energization of the solenoid 2| which may be efiected by any suitable means (not shown). When energized, the solenoid 2| attracts its armature H5 and through the links I23 pulls the knee pin 19 of the main toggle upwardly. Since, at this time, the lever 69 including the pivot pin 11 is held in a fixed position by the tripping toggle 8385 and the latch 97, the force applied by the solenoid to straighten the main toggle 656'I operates the switch arm 29 to simultaneously close the 'contacts of all of the poles of the breaker.

The trip device I9 comprises a tripping solenoid I2'I (Fig. 1) which may be energized preferably by low voltage current through suitable control means (none being shown) upon the occurrence of predetermined abnormal conditions such as a phase-to-phas'e or phase-to-ground fault involving any one or more of the phase circuits controlled by the breaker. The solenoid I2l is rigidly supported by an angle bracket I29 having one leg |3| rigidly secured as by welding to one of the side members 33 of the main frame 35. Secured to the leg I 3| of the bracket I29 is a pair of spaced arms I33 (Fig. 2) which between them support, a. pivot pin I35 upon which is pivotally mounted a trip leverl3I the right-hand end (Fig. l) of which lies above a trip rod I39 adapted to be thrust upwardly by the armature (not shown) of the tripping solenoid I2'I. The left-hand end (Fig. l) of the trip lever I31 carries an adjusting screw NI streets which is locked in its adjusted position by a lock nut I 43. The lower end of the adjusting screw MI is adapted to engage an ear I45 formed laterally from the latch member 91.

The latching position of the latch member 9'! is adjustable by means of an adjusting screw I mounted in an arm I49 of the bracket I29 and locked in its adjusted position by a lock nut I5I. A projection I53 of the latch member 91 is biased against the end of the screw I4! by means of a spring I55 compressed between one of the arms 533 and the projection I53;

When the tripping solenoid I21 (Fig. 1) is energized the trip rod I39 is thrust upwardly and engages and rocks the trip lever I31 counterclockwise about its pivot I35, causing the screw I II to rock the latch member 91 also in a counterclockwise direction (Fig. 2) This action releases tripping toggle 8385 which collapses and effects opening of the breaker as previously set forth.

The speed and sudden force with which an alternating-current solenoid when energized picks up and operates its armature is common knowledge. The sudden force with which the alternating-current solenoid picks up and starts the movement of the armature and the operating mechanism in closing direction creates a shock of sufiicient magnitude to start the light-load latch in releasing or tripping direction. Also the sudden stopping of the armature and the operating mechanism, when they arrive at the closed circuit position, creates a very heavy shock to the framework and mechanism of the circuit breaker which, at times, results in moving the light-load latch member 9'! to unlatching position, and since the circuit breaker is trip-free of the closing solenoid, causes false opening of the contacts. A desirable feature of circuit breakers for controlling and protecting network systems in relatively light-load density areas is to effect tripping out of the circuit breakers by the use of low-voltage current. This, however, necessitates the retention of the light-trip load tripping mechanism which is susceptible to actuation in response to the shock created by closing of the breaker.

In order to prevent tripping the breaker in response to the shock of the solenoid pick up and slam, means is provided which is set in motion by the closing mechanism during a closing stroke to prevent movement of the latch to unlatching position for a predetermined tim interval immediately before and after the closing means is arrested in the closed position. This means comprises an unbalanced mass or weight I51 (Fig. 2) which is pivotally mounted on a rod I59 supported in the main frame 35. A projection IEI of the weight I5? carries an adjusting screw I63 which is locked in its adjusted position by means of a lock nut I65. The lower end of the screw I63 is biased into engagement with the main toggle E5-61 adjacent the knee thereof by means of a spring IB'I coiled aboutthe rod I53 and having one end bearing-against the rod IE2 and the other end hooked over the projection I6 I. 7

When the circuit breaker is tripped open and the main toggle 65-431 breaks overcenterbelow the line '65, H the spring I6! rotates the weight I51 counterclockwise until itis arrested by engagement with the angle portion I89 of a bracket III secured to one of the side members 33 of the frame. During a closing stroke of the closing mechanism, the toggle 65-6'I strikes the screw I63 and rotates the weight I51 clockwise to move an arcuatesurface I13 of the weight into the path of tripping movement of the "latch. member 9T thus blocking unlatching movement of the latch in response to the terminal shock or the closing mechanism when the armature II 5 seats. The reaction of the latch member 9'! to the starting shock of the solenoid is slower than the movement of the operating mechanism. If the latch member 91 starts in unlatching direction in response to the starting shock of the closing solenoid, it will not reach the unlatching position be fore the toggle 6'I engages and drives the weight I57 toward its blocking position. The weight I57 will, therefore, engage the rounded end of the latch member and drive it back to latching position. The inertia of the mass or weight I5? causes it to continue its clockwise movement until the head of the screw I63 strikes the rod I92 whereupon the weight rebounds and moves counterclockwise to the position shown in Fig. 2. The time interval required for the weight I57 to complete its oscillation is sufiicient not only to prevent unlatching movement of the latch 91 at the instant the armature seats, but also prevents unlatching in response to secondary or reactive shocks occurring within a predetermined time interval following completion of the closing movement of the mechanism.

Having described a preferred embodiment of the invention in accordance with the patent statutes, it is to be understood that various changes and modifications may be made in the particular embodiment disclosed without departing from some of the essential features of the invention.

We claim as our invention:

1. A circuit breaker comprising power operated means for closing the breaker, said power operated means causing a shock at the end of the closing operation, tripping means including a latch operable to efiect automatic opening of the breaker, and means engaged and actuated by said closing means prior to the end of said closing operation to a position to block tripping operation of said latch during the terminal movement of said closing means.

2. A circuit break-er comprising power operated closing means for closing the breaker, said closing means causing a shock at the end of the closing stroke, tripping means including a latch operable to effect automatic opening of the break-- er, and means actuated by said closing means near the end of the closing stroke and prior to the occurrence of said shock to block tripping operation of said latch for a predetermined time interval.

3. A circuit breaker comprising power operated closing means for closing said breaker, closing means generating a shock at the end of the closing operation, tripping means including a latch operable to effect automatic opening of said breaker, and means engaged and actuated by said closing means before the end of the closing operation for blocking tripping operating movement of said tripping means in response to sudden shocks generated by the terminal movement of said closing means.

a. A circuit breaker comprising power operated means for closing said breaker, said closing means creating a shock at the end of the closing operation, tripping means operable to efiect automatic opening of said breaker, and means comprising an unbalanced mass engaged said closing means and moved to a position to block tripping operation of said tripping means during the terminal movement of said closing means and before the occurrence of said shock.

55. In a circuit breaker comprising power operate'd closing means for closing said breaker, said closing means generating a shock at the end of the closing stroke, tripping means operable to effect automatic opening of said breaker, and means-comprising an unbalanced mass set in motion by said closing means near the end of the closing movement but before the occurrence of said shock and moved to a position to block tripping operating movement of said tripping means in response to sudden shocks or jarring forces generated by the terminal movement of said closing means.

6. In a circuit breaker comprising relatively movable contact means, operating mechanism therefor comprising an operating toggle and power operated closing means for operating said toggle to close said contacts, said closing means causing a shock at the end of the closing stroke, a tripping toggle releasably restraining said operating toggle, tripping means operable to release said tripping toggle to cause automatic opening of said contact means, and means engaged and moved by said operating toggle during a closing operation and before the occurrence of said shock to a position to block operation of said tripping means and prevent release of said tripping toggle during the terminal closing movement of said operating mechanism.

7. In a circuit breaker comprising relatively movable contact means, operating mechanism therefor comprising an operating toggle and power operated closing means for operating said toggle to close said contacts, tripping means including a latch releasably restraining said operating toggle, said tripping means being operable to release said operating toggle to cause automatic opening of said contact means, and means comprising an unbalanced mass engaged b said operating toggle during a closing operation but before the end of said operation and moved to a position to block releasing operation of said latch during the terminal closing movement of said operating mechanism.

8. In a circuit breaker comprising relatively movable contact means, operating mechanism therefor comprising an operating toggle and power operated means for actuating said toggle to close said contact means, tripping means comprising a tripping toggle releasably restraining said operating toggle in operative position, latch means releasably restraining said tripping toggle in restraining position, said tripping toggle being operable to release said operating toggle to thereby efiect automatic opening of said contact means, and means engaged and actuated by said operating mechanism before the end of a closing operation to a position to oppose operation of said latch means for a predetermined time interval.

9. In a circuit breaker comprising relatively movable contact means, operating mechanism therefor comprising an operating toggle and power operated means for actuating said toggle to close said contact means, tripping means comprising a tripping toggle releasably restraining said operating toggle in operative position, latch means restraining said tripping toggle in restraining position, said tripping toggle being operable to release said operating toggle to thereby efiect automatic opening of said contact means, and means comprising a mass engaged and set in motion by said operating mechanism before the end of a closing operation to prevent operation of said latch means for a predetermined time interval.

10. In a circuit breaker comprising relatively movable contact means, operating means therefor comprising a main operating toggle and power operated means for operating said main toggle to close said contact means, a second toggle releasably restraining said main toggle in operative position and operable to release said main toggle to efiect automatic opening of said contact means, restraining means releasably restraining said second toggle in restraining position means for operating said restraining means to release said second toggle, and means disposed to be engaged and actuated by said main toggle during a closing operation to prevent operation of said restraining means for a predetermined time interval.

11. In a circuit breaker comprising relatively movable contact means, operating means therefor comprising a main operating toggle and power operated means for operating said main toggle to close said contact means, a second toggle releasably restraining said main toggle in operative position and operable to release said main toggle to effect automatic opening of said contact means, restraining means releasably restraining said second toggle in restraining position, means for operating said restraining means to release said second toggle, and means comprising a mass engaged and set in motion by said main toggle during a closing operation to prevent operation of said restraining means for a predetermined time interval.

12. In a circuit breaker comprising relatively movable contact means, operating means therefor comprising a .main toggle and power operated means for operating said main toggle to close said contact means, a second toggle releasably restraining said main toggle in operative position and operable to release said main toggle to eifect automatic opening of said contact means, latch means releasably restraining. said second toggle in restraining position, means for operating said latch means to release said second toggle, and means comprising an unbalanced mass engaged and set in motion by said main toggle during a closing movement to prevent operation of said latch means for a predetermined time interval.

13. In a circuit breaker comprising relatively movable contact means, operating mechanism therefor comprising a main toggle, power operated means for operating said main toggle to close said contact means, a trippin toggle releasably restraining said main toggle in operative position, a light-load latch member releasably restraining said tripping toggle in restraining position, tripping means actuating said light-load latch member to effect release of said tripping toggle, a pivoted mass, and means operable by said main toggle near the end of a closing operation for moving said mass into the path of tripping movement of said light-load latch member to thereby prevent tripping movement of said latch member in response to sudden shocks generated by the final closing move-- ment of said mechanism.

14. In a circuit breaker comprising relatively movable contact means, operating mechanism therefor comprising a linkage, power operated means for operating said linkage to close said contact means, a toggle for releasably restraining said linkage in operative position, a lightload latch member for releasably restraining said toggle in restraining position, tripping means for actuating said light-load latch member to efiect opening of said contact means, a

pivoted mass disposed to be moved to a position for blocking tripping movement of said latch member, and means on said linkage for engaging and moving said mass to blocking position near the end of a closing operation to prevent tripping movement of said latch in response to the shock of the closing operation.

15. In a circuit breaker comprising relatively movable contact means, operating mechanism for said contact means comprising a linkage, power operated means for operating said linkage to close said contact means, a light-load latch member for releasably restraining said linkage in operative position, tripping means for actuating said latch member to release said linkage and efiect opening of said contact means, a pivoted member disposed to be moved to a blocking position for blocking movement of said latch member in tripping direction in response to the shock of the terminal closing movement of the operating mechanism, means on said linkage for engaging and moving said blocking member to blocking position, and adjustable 10 means for adjustably determining the point during the closing operation at which the linkage will engage said blocking member.

GEORGE G. GRISSINGER. BERNARD G. TREMBLAY.

REFERENCES CITED The following references are of record in the file of this patent:

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